The Spring TestContext Framework provides consistent loading of Spring ApplicationContexts and caching of those contexts. Support for the caching of loaded contexts is important, because if you are working on a large project, startup time may become an issue - not because of the overhead of Spring itself, but because the objects instantiated by the Spring container will themselves take time to instantiate. For example, a project with 50-100 Hibernate mapping files might take 10-20 seconds to load the mapping files, and incurring that cost before running every single test in every single test fixture will lead to slower overall test runs that could reduce productivity.

Test classes provide an array containing the resource locations of XML configuration metadata - typically on the classpath - used to configure the application. This will be the same, or nearly the same, as the list of configuration locations specified in web.xml or other deployment configuration.

By default, once loaded, the configured ApplicationContext will be reused for each test. Thus the setup cost will be incurred only once (per test fixture), and subsequent test execution will be much faster. In the unlikely case that a test may 'dirty' the application context, requiring reloading - for example, by changing a bean definition or the state of an application object - Spring's testing support provides a mechanism to cause the test fixture to reload the configurations and rebuild the application context before executing the next test.

See: context management and caching with the TestContext Framework.

When the TestContext framework loads your application context, it can optionally configure instances of your test classes via Dependency Injection. This provides a convenient mechanism for setting up test fixtures using pre-configured beans from your application context. A strong benefit here is that you can reuse application contexts across various testing scenarios (e.g., for configuring Spring-managed object graphs, transactional proxies, DataSources, etc.), thus avoiding the need to duplicate complex test fixture set up for individual test cases.

As an example, consider the scenario where we have a class, HibernateTitleDao, that performs data access logic for say, the Title domain object. We want to write integration tests that test all of the following areas:

See: dependency injection of test fixtures with the TestContext Framework.

One common issue in tests that access a real database is their affect on the state of the persistence store. Even when you're using a development database, changes to the state may affect future tests. Also, many operations - such as inserting or modifying persistent data - cannot be performed (or verified) outside a transaction.

The TestContext framework addresses this issue. By default, the framework will create and roll back a transaction for each test. You simply write code that can assume the existence of a transaction. If you call transactionally proxied objects in your tests, they will behave correctly, according to their transactional semantics. In addition, if test methods delete the contents of selected tables while running within a transaction, the transaction will roll back by default, and the database will return to its state prior to execution of the test. Transactional support is provided to your test class via a PlatformTransactionManager bean defined in the test's application context.

If you want a transaction to commit - unusual, but occasionally useful when you want a particular test to populate or modify the database - the TestContext framework can be instructed to cause the transaction to commit instead of roll back via the @TransactionConfiguration and @Rollback annotations.

See: transaction management with the TestContext Framework.

The Spring TestContext Framework provides several abstract support classes that can simplify writing integration tests. These base test classes provide well defined hooks into the testing framework as well as convenient instance variables and methods, allowing access to such things as:

In addition, you may find it desirable to provide your own custom, application-wide superclass for integration tests that provides further useful instance variables and methods specific to your project.

See: support classes for the TestContext Framework.

The core of the framework consists of the TestContext and TestContextManager classes and the TestExecutionListener interface. A TestContextManager is created on a per-test basis. The TestContextManager in turn manages a TestContext which is responsible for holding the context of the current test. The TestContextManager is also responsible for updating the state of the TestContext as the test progresses and delegating to TestExecutionListeners, which instrument the actual test execution (e.g., providing dependency injection, managing transactions, etc.). Consult the JavaDoc and the Spring test suite for further information and examples of various configurations.

The following three sections explain how to configure the TestContext framework via annotations and provide working examples of how to actually write unit and integration tests with the framework.

Each TestContext provides context management and caching support for the test instance for which it is responsible. Test instances do not automatically receive access to the configured ApplicationContext; however, if a test class implements the ApplicationContextAware interface, a reference to the ApplicationContext will be supplied to the test instance (provided the DependencyInjectionTestExecutionListener has been configured, which is the default). Note that AbstractJUnit38SpringContextTests, AbstractJUnit4SpringContextTests, and AbstractTestNGSpringContextTests already implement ApplicationContextAware and therefore provide this functionality out-of-the-box.

	@Autowired ApplicationContext
	As an alternative to implementing the ApplicationContextAware interface, your test class can have its application context injected via the @Autowired annotation on either a field or setter method, for example: @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration public class MyTest { @Autowired private ApplicationContext applicationContext; // class body... }

In contrast to the now deprecated JUnit 3.8 legacy class hierarchy, test classes which use the TestContext framework do not need to override any protected instance methods to configure their application context. Rather, configuration is achieved merely by declaring the @ContextConfiguration annotation at the class level. If your test class does not explicitly declare any application context resource locations, the configured ContextLoader will determine how and whether or not to load a context from a default set of locations. For example, GenericXmlContextLoader - which is the default ContextLoader - will generate a default location based on the name of the test class. If your class is named com.example.MyTest, GenericXmlContextLoader will load your application context from "classpath:/com/example/MyTest-context.xml".

package com.example;

@RunWith(SpringJUnit4ClassRunner.class)
// ApplicationContext will be loaded from "classpath:/com/example/MyTest-context.xml"
@ContextConfiguration
public class MyTest {
    // class body...
}

If the default location does not suit your needs, you are free to explicitly configure the locations attribute of @ContextConfiguration (see code listing below) with an array containing the resource locations of XML configuration metadata (assuming an XML-capable ContextLoader has been configured) - typically on the classpath - used to configure the application. This will be the same, or nearly the same, as the list of configuration locations specified in web.xml or other deployment configuration. As an alternative you may choose to implement and configure your own custom ContextLoader.

@RunWith(SpringJUnit4ClassRunner.class)
// ApplicationContext will be loaded from "/applicationContext.xml" and "/applicationContext-test.xml"
// in the root of the classpath
@ContextConfiguration(locations={"/applicationContext.xml", "/applicationContext-test.xml"})
public class MyTest {
    // class body...
}

@ContextConfiguration supports an alias for the locations attribute via the standard value attribute. Thus, if you do not need to configure a custom ContextLoader, you can omit the declaration of the locations attribute name and declare the resource locations using the shorthand format demonstrated in the following example. @ContextConfiguration also supports a boolean inheritLocations attribute which denotes whether or not resource locations from superclasses should be inherited. The default value is true, which means that an annotated class will inherit the resource locations defined by an annotated superclass. Specifically, the resource locations for an annotated class will be appended to the list of resource locations defined by an annotated superclass. Thus, subclasses have the option of extending the list of resource locations. In the following example, the ApplicationContext for ExtendedTest will be loaded from "/base-context.xml" and "/extended-context.xml", in that order. Beans defined in "/extended-context.xml" may therefore override those defined in "/base-context.xml".

@RunWith(SpringJUnit4ClassRunner.class)
// ApplicationContext will be loaded from "/base-context.xml" in the root of the classpath
@ContextConfiguration("/base-context.xml")
public class BaseTest {
    // class body...
}

// ApplicationContext will be loaded from "/base-context.xml" and "/extended-context.xml"
// in the root of the classpath
@ContextConfiguration("/extended-context.xml")
public class ExtendedTest extends BaseTest {
    // class body...
}

If inheritLocations is set to false, the resource locations for the annotated class will shadow and effectively replace any resource locations defined by a superclass.

By default, once loaded, the configured ApplicationContext will be reused for each test. Thus the setup cost will be incurred only once (per test fixture), and subsequent test execution will be much faster. In the unlikely case that a test may dirty the application context, requiring reloading - for example, by changing a bean definition or the state of an application object - you may annotate your test method with @DirtiesContext (assuming DirtiesContextTestExecutionListener has been configured, which is the default) to cause the test fixture to reload the configurations and rebuild the application context before executing the next test.

When you configure the DependencyInjectionTestExecutionListener - which is configured by default - via the @TestExecutionListeners annotation, the dependencies of your test instances will be injected from beans in the application context you configured via @ContextConfiguration by Setter Injection, Field Injection, or both, depending on which annotations you choose and whether you place them on setter methods or fields. For consistency with the annotation support introduced in Spring 2.5, you may choose either Spring's @Autowired annotation or the @Resource annotation from JSR 250. The semantics for both are consistent throughout the Spring Framework. For example, if you prefer autowiring by type, annotate your setter methods or fields with @Autowired. On the other hand, if you prefer to have your dependencies injected by name, annotate your setter methods or fields with @Resource.

	Tip
	The TestContext framework does not instrument the manner in which a test instance is instantiated. Thus the use of @Autowired for constructors has no effect for test classes.

Since @Autowired performs autowiring by type, if you have multiple bean definitions of the same type, you cannot rely on this approach for those particular beans. In that case, you can use @Resource for injection by name. Alternatively, if your test class has access to its ApplicationContext, you can perform an explicit lookup using (for example) a call to applicationContext.getBean("titleDao"). A third option is to use @Autowired in conjunction with @Qualifier.

If you don't want dependency injection applied to your test instances, simply don't annotate any fields or setter methods with @Autowired or @Resource. Alternatively, you can disable dependency injection altogether by explicitly configuring your class with @TestExecutionListeners and omitting DependencyInjectionTestExecutionListener.class from the list of listeners.

Consider the scenario where we have a class, HibernateTitleDao (as outlined in the Goals section). First, let's look at a JUnit 4.5 based implementation of the test class itself which uses @Autowired for field injection (we will look at the application context configuration after all sample code listings). Note: The dependency injection behavior in the following code listings is not in any way specific to JUnit 4.5. The same DI techniques can be used in conjunction with any testing framework.

@RunWith(SpringJUnit4ClassRunner.class)
// specifies the Spring configuration to load for this test fixture
@ContextConfiguration("daos.xml")
public final class HibernateTitleDaoTests {

    // this instance will be dependency injected by type
    @Autowired    
    private HibernateTitleDao titleDao;

    public void testLoadTitle() throws Exception {
        Title title = this.titleDao.loadTitle(new Long(10));
        assertNotNull(title);
    }
}

Alternatively, we can configure the class to use @Autowired for setter injection.

@RunWith(SpringJUnit4ClassRunner.class)
// specifies the Spring configuration to load for this test fixture
@ContextConfiguration("daos.xml")
public final class HibernateTitleDaoTests {

    // this instance will be dependency injected by type
    private HibernateTitleDao titleDao;

    @Autowired
    public void setTitleDao(HibernateTitleDao titleDao) {
        this.titleDao = titleDao;
    }

    public void testLoadTitle() throws Exception {
        Title title = this.titleDao.loadTitle(new Long(10));
        assertNotNull(title);
    }
}

Now let's take a look at an example using @Resource for field injection.

@RunWith(SpringJUnit4ClassRunner.class)
// specifies the Spring configuration to load for this test fixture
@ContextConfiguration("daos.xml")
public final class HibernateTitleDaoTests {

    // this instance will be dependency injected by name
    @Resource
    private HibernateTitleDao titleDao;

    public void testLoadTitle() throws Exception {
        Title title = this.titleDao.loadTitle(new Long(10));
        assertNotNull(title);
    }
}

Finally, here is an example using @Resource for setter injection.

@RunWith(SpringJUnit4ClassRunner.class)
// specifies the Spring configuration to load for this test fixture
@ContextConfiguration("daos.xml")
public final class HibernateTitleDaoTests {

    // this instance will be dependency injected by name
    private HibernateTitleDao titleDao;
    
    @Resource
    public void setTitleDao(HibernateTitleDao titleDao) {
        this.titleDao = titleDao;
    }

    public void testLoadTitle() throws Exception {
        Title title = this.titleDao.loadTitle(new Long(10));
        assertNotNull(title);
    }
}

The above code listings use the same XML context file referenced by the @ContextConfiguration annotation (i.e., "daos.xml") which looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" 
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans 
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <!-- this bean will be injected into the HibernateTitleDaoTests class -->
    <bean id="titleDao" class="com.foo.dao.hibernate.HibernateTitleDao">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>
    
    <bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
        <!-- dependencies elided for clarity -->
    </bean>

</beans>

Note

If you are extending from a Spring-provided test base class that happens to use @Autowired on one of its setters methods, you might have multiple beans of the affected type defined in your application context: e.g. multiple DataSource beans. In such a case, you may override the setter and use the @Qualifier annotation to indicate a specific target bean as follows: ... @Override @Autowired public void setDataSource(@Qualifier("myDataSource") DataSource dataSource) { super.setDataSource(dataSource); } ... The specified qualifier value indicates the specific DataSource bean to inject, narrowing the set of type matches to a specific bean. Its value is matched against <qualifier> declarations within the corresponding <bean> definitions. The bean name is used as a fallback qualifier value, so you may effectively also point to a specific bean by name there (as shown above, assuming that "myDataSource" is the bean id). If there is only one DataSource bean to begin with, then the qualifier will simply not have any effect - independent from the bean name of that single matching bean. Alternatively, consider using the @Resource annotation on such an overridden setter methods, defining the target bean name explicitly - with no type matching semantics. Note that this always points to a bean with that specific name, no matter whether there is one or more beans of the given type. ... @Override @Resource("myDataSource") public void setDataSource(DataSource dataSource) { super.setDataSource(dataSource); } ...

In the TestContext framework, transactions are managed by the TransactionalTestExecutionListener, which is configured via the @TestExecutionListeners annotation by default, even if you do not explicitly declare @TestExecutionListeners on your test class. To enable support for transactions, however, you must provide a PlatformTransactionManager bean in the application context loaded via @ContextConfiguration semantics. In addition, you must declare @Transactional either at the class or method level.

For class-level transaction configuration (i.e., setting the bean name for the transaction manager and the default rollback flag), see the @TransactionConfiguration entry in the annotation support section.

There are several options for configuring transactions for individual test methods. If transactions are not enabled for the entire test class, methods may be explicitly annotated with @Transactional. Similarly, if transactions are enabled for the entire test class, methods may be explicitly flagged not to run within a transaction by annotating them with @NotTransactional. To control whether or not a transaction should commit for a particular test method, you may use the @Rollback annotation to override the class-level default rollback setting.

Note that AbstractTransactionalJUnit38SpringContextTests, AbstractTransactionalJUnit4SpringContextTests, and AbstractTransactionalTestNGSpringContextTests are pre-configured for transactional support at the class level.

You will occasionally find that you need to execute certain code before or after a transactional test method but outside the transactional context, for example to verify the initial database state prior to execution of your test or to verify expected transactional commit behavior after test execution (e.g., if the test was configured not to roll back the transaction). TransactionalTestExecutionListener supports the @BeforeTransaction and @AfterTransaction annotations exactly for such scenarios. Simply annotate any public void method in your test class with one of these annotations, and the TransactionalTestExecutionListener will ensure that your before transaction method or after transaction method is executed at the appropriate time.

	Tip
	Any before methods (e.g., methods annotated with JUnit 4's @Before) and any after methods (e.g., methods annotated with JUnit 4's @After) will be executed within a transaction. In addition, methods annotated with @BeforeTransaction or @AfterTransaction will naturally not be executed for tests annotated with @NotTransactional.

The following JUnit 4 based example displays a fictitious integration testing scenario highlighting several of the transaction-related annotations. Consult the annotation support section of the reference manual for further information and configuration examples.

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
@TransactionConfiguration(transactionManager="txMgr", defaultRollback=false)
@Transactional
public class FictitiousTransactionalTest {

    @BeforeTransaction
    public void verifyInitialDatabaseState() {
        // logic to verify the initial state before a transaction is started
    }

    @Before
    public void setUpTestDataWithinTransaction() {
        // set up test data within the transaction
    }

    @Test
    // overrides the class-level defaultRollback setting
    @Rollback(true)
    public void modifyDatabaseWithinTransaction() {
        // logic which uses the test data and modifies database state
    }

    @After
    public void tearDownWithinTransaction() {
        // execute "tear down" logic within the transaction
    }

    @AfterTransaction
    public void verifyFinalDatabaseState() {
        // logic to verify the final state after transaction has rolled back
    }

    @Test
    @NotTransactional
    public void performNonDatabaseRelatedAction() {
        // logic which does not modify database state
    }
}